Services: Unidirectional Flushing

Tata & Howard prepared a sequential Unidirectional Flushing Plan (UDF) for the Town of Wayland’s water distribution system, utilizing the existing hydraulic model to develop flushing sequences for hydrants and valves to be operated. The sequences were updated from the original plan to review anticipated flushing velocities and identify areas of potential low-pressure concerns. Field assistance was provided during the implementation of the updated plan. A summary report was provided, identifying the amount of water used during flushing, areas of hydrant or valve mapping discrepancies, and areas with broken or inoperable hydrants and valves.

Tata & Howard recently developed a unidirectional flushing (UDF) program for the Town of Shrewsbury, MA. The project included converting the existing water distribution system hydraulic model from WaterGEMs to InfoWater, preparing water system flushing maps, delineating flushing zones, and preparing a sequential UDF for the water distribution system from sources to system extremities following the American Water Works Association (AWWA) published guidelines referred to as “Rules for Flushing.” The program successfully idenitified sequences of valves to close, hydrants to flush, flow rates, and required duration. Worksheets were prepared for each sequence, including identification of hydrants and valves to be operated, pipes to be flushed, approximate discharge flow, and recommended flushing duration.

Unidirectional Flushing
Tata & Howard provided assistance during the City’s unidirectional flushing program. As part of the work, Tata & Howard recorded the flow from the hydrants, noted any changes in the plan, and noted any defective hydrants or valves. When completed, a summary report outlining the total usage of water and recommended improvements to the flushing program was provided.

Water Mains and Capital Efficiency Plan™Tata & Howard also provided design and construction services for approximately 5,600 feet of new 8-inch water main and approximately 950 feet of new 12-inch water main throughout the City. Plans were created using available GIS data from the City and field verification. These water mains also included crossing two MWRA transmission mains and crossing the Lynn Fells Parkway. The Lynn Fells Parkway crossing required permitting with the Department of Conservation and Recreation and a traffic management plan. This work was funded through the MWRA. As part of the project, Tata & Howard updated and verified the City’s existing hydraulic model, which has over 80 miles of water main. Work included two days of fire flow tests throughout the City and allocation of demands using up-to-date billing and parcel data. The locations of the new water mains were selected based on preliminary recommendations identified in the Capital Efficiency Plan™ that was prepared by Tata & Howard. The Capital Efficiency Plan™ identified and prioritized areas for improvement within the distribution system. Our services included evaluating the condition of the existing distribution system infrastructure to determine the adequacy of meeting present and future demands, assessing and prioritizing system improvements, reviewing and evaluating typical fire flows throughout the system, creating a pipe asset management rating system, and recommending improvements to the distribution system.

Download a whitepaper detailing a comprehensive summary of the UDF by clicking the link below: